It sure did back in 1996 with my Pentium 166 MHz tower running with 32 MB, if memory does not fail me.

Oh, it sure did, when it worked. My most prominent memory of Mandrake, however, is version 6.0 where they used pgcc 1.1.3. Seg faults and signal 11s all over the place when there was not a single thing wrong with my hardware, and outdated packages to boot.

I don't know, all the tests I've seen suggested (if memory does not fail me) that such compile-time optimisations usually give negligible gains, at best (and, in very memory & bandwidth constrained situations, sometimes harm - but really, also negligible)

If that was about "feel" ...easy to fall into ~placebo without proper ABX procedures, with such minuscule differences. RAM amount and HDD speed were more responsible for feel also back then.
(and certainly are on my dual PII 266 that I keep around)